This invention relates to photoresist compositions that comprise a carbamate compound that comprises 1) a carbamate group and 2) an ester group. Preferred photoresists of the invention may comprise a resin with acid-labile groups; an acid generator; and a carbamate compound that can function to decrease undesired photogenerated-acid diffusion out of unexposed regions of a photoresist coating layer.
Photoresists are photosensitive films for transfer of images to a substrate. They form negative or positive images. After coating a photoresist on a substrate, the coating is exposed through a patterned photomask to a source of activating energy, such as ultraviolet light, to form a latent image in the photoresist coating. The photomask has areas opaque and transparent to activating radiation that define an image desired to be transferred to the underlying substrate.
Known photoresists can provide features having resolution and size sufficient for many existing commercial applications. However for many other applications, the need exists for new photoresists that can provide highly resolved images of sub-quarter-micron (<0.25 μm) dimension.
Various attempts have been made to alter the make-up of photoresist compositions to improve performance of functional properties. Among other things, a variety of basic compounds have been reported for use in photoresist compositions. See, e.g., U.S. Pat. Nos. 6,486,058, 6,607,870 and 7,379,548, as well as Japanese published patents JP 1103086 and 1231538. See also U.S. 2011/0223535, US 2012/0077120 and US 2012/0141938.
Short-wavelength imaging such as 193 nm also has been utilized to produce highly resolved small features. Extreme ultraviolet (EUV) and e-beam imaging technologies also have been employed. See U.S. Pat. No. 7,459,260. EUV utilizes short wavelength radiation, typically between 1 nm to 40 nm, with 13.5 nm radiation often employed.
EUV photoresist development continues to be a challenging issue for EUV Lithography (EUVL) technology implementation. Required are development of materials that can provided highly resolved fine features, including low linewidth roughness (LWR), and sufficient sensitivity to afford wafer throughput.